Circuit-breaker for electric circuits.



F. L. SESSIONS.

CIRCUIT BREAKER FOR ELECTRIC CIRCUITS.

APPLICATION FILED FEB.25,1904.

Patented Sept. 2,1913.

3 SHEETS-SHEET 1.

F. L. SESSIONS.

CIRCUIT BREAKER FOB. ELECTRIC CIRGULTS.

auueui oz X 1 messes F. L. SESSIONS.

CIRCUIT BREAKER FOR ELECTRIC CIRCUITS.

APPLICATION FILED FEB. 25, 1904. I I 4 Pacented Sept. 2, 1913 3SHEETS-SHEET 3k aYwK 5:214, 7

a mama ring tinirnn rgnnr ormcn.

rnntx r. sessions, or comamnus, omo, micron. n? unsnn Assmnmnnrs, 'ro

mm: inn-m -muracwnmc comnaiw,

GIMHIT-BBEAKEB B insecu e, usters Specification Letters Mont.

Patented Sept. 2, 1913.

Anghcation'thd mini-y w, 386. 803a 1S0. 195,906.

Ithas, for one of its objects to provide a circuit breaker. in which thearcing occurwithin the mechanism atthe' instant of the final break ofthe circuit therein is caused to take placebetween carbon contacts afterthe metallic contacts which are used have been separated, so as to avoidrapid deterioration of .the inetal contacts.

Another. object of my invention is to provide means'for tuning theaction of the cirnet. Itis preferably tor-med inte cuit breakingmechanism under an over-load of current on the circuit, whereby thecircuit, will not be broken instantaneously, but the said breaking willoccur after a predetermined interval-of continuance-of the excess ofcurrent.

Figure 1. is a face view of a mechanism embodying my improvements, theface plate of the casing being removed. Fig. 2 1s aview partlyv in faceelevation, 'withthe plate removed, and partly in vertical section Fig. 3is a perspective showing the bracket the casing, the magnetand some ofthe upper contacts and terminals. Fig. 4'is a perspective showing thecontact separatinq rod, the trigger, the tripping rod and ban lever forclosing the circuit. Fig. 5 is a central vertical section of theapparatus. Fig. 6 is a cross-section on line 66 of Fig.

Fig. 7 is a horizontal section on the line 77 of Fig. 5. Fi 8 is avertical section showing the checking or retarding device. Fig. 9 is asection of the spring and spring actuated devices which hold thearmature in normal position. Fig. 10 is an end view of the parts. inFig.9.

In the drawings the apparatus is shown as provided with a casing havingthe back ovements in Circuit-Break n 18, the top walllS, the bottom 20,the side walls 18", and the front detachable wall or cover 19. saidbottom and side walls belng preferably formed of non-magnetic material.

A represents a block of insulating material secured in posltion in theupper. part of the casing. It serves to providefan insulat ing supportfor certain of theelectric conductors within the casing.

, the upper end. or terminal 22 is a binding postsecured to theunderside of the bloc A and? adapted to receive. the conductor throughwhich the current enters the mechanism. 22? indicates the base portionof the said binding post to which Moi the coil of the blow-out magnet 24is This coil, as a whole, is of the'character-ofa,

spool, with suitableinsulation-between its convolutions.

12 indicates the metallic core of the magal with the back wall 18' andlike the sai wall is This core at its forward end is bifurcated, as

' shown at 12, 12.

12", 12 are projections carried b the back piece 18, one arranged ateither side of the casing and adapted'to serve as poles for the magnet24.

The current after pas 'ng through all the convolutions of the coil,travels over the outgoing conductor section 25 to the stationary.

contact plate or brush 2.. This brush or contact late is secured toinsulat-in plate A and is formed with the under-s'oping or taperedsurface 2.

3" is a binding-post secured to the insulating block A and adapted toreceive the conductor through which the current passes from themechanism. This binding-post has extending inward from it the contactplate or brush 3 having its under edge sloping or tapered as indicatedat 3.

4 is a carbon block secured to the under surface of the contact )late 3and 6 is a carbon block secured to t e under surface of the contactplate 2.

1 indicates as an entirety a switch or mov- 3 of the contact'plates 2, 3with which they um adapted to engage.

cured in the holder 30 beneath the plates of copper therein and adaptedto have its ends "contact with .the lower-most points of the blocks 4and 5 respectively. These carbon able circuit closing member. Thisswitch preferably consists of two sets of movable contact engagingelements or brushes. -The upper one 30 is formed of a series of laminae1 or pla es of copper securely fastened together and held by aninsulating holder 3O which is secured tothe upper end of the rod 29. Thelaminae, or layers of copper increase in length downward so as toprovide tapering or sloping ends-tor the brush which correspond to thetapered edges 2,

1' is a spring seblocks 5 and 7 .are preferably secured in holders 8which are pivotally mounted in bearing blocks 8" secured to the oppositeends'of the-spring 8. 8 are springs for holding the carbon holdersyieldingly relative to the said spring 8.

26 is a flexible conductor held within the insulated holder 30 andhaving its ends secured in the carbon holders 8 and immediately adjacent'to the carbon blocks 5 and 7 It is made of metal which is a goodconductor of elec tricity and is adapted to in- .the spring being conipisure good electrical connection between. the carbon blocks.

The path of the current through the mechanism is as follows: It entersat the binding-post 22 and passes throughthe coil 24 to the stationarycontact 2. When the circuit is closed the current passes from thecontact plate 2 through the brushes carried by the switch 1 t0.thecontact plate 3 and thence through the binding post, 3 to the main.

In order to break thecircuit I provide mechanism for drawing the copperplates or ,laminae'of the brush 30 away from the contacts at 2 and 3 andsubsequently separating the contacts 4:, 5 and (i, 7. As stated 5 thesebrushes are supported at the upper end of the carrier or rod 29. Thisrod is held and guided by a collar 29 which is socured at 29 to the core12' of the magnet and extends down between the project-ions 12 thereof.

28 is a spring surrounding the rod-29 and hearing upward against thecollar 29 and downward against the r l: 17 29 on the rod, d when the rodis forced upward to cause the circuit within the mechanism to be closedand, being under compression, -is ready to quickly draw or thrust therod downward when the latter is.

released from; the locking device, to be described. The latter consistsof a triggerlike device, indicated by 36, it having -up'- right legs,36' which are pivoted at .37 to a.

lug 37 on the bottom wall 20 of the casing.

At its upper end this trigger-like device 36 has outwardl straddle theower s uared portion of the rod 29. The upper e ges of these arms 36"'are curved, the curvature being concentric with the axis ofthe pivotalconnection at 37.

35 are anti-friction rollers mounted on studs or pins carried by the rod29. They are adapted to rest and roll upon the aforesaid curved edgesof'the arms 36*.

.38 is a. spring secured at one end 'toan arm 38 on the trigger device36 and having its other end adapted to rest on the bottom 4 wall 20 ofthe casing. This springEt'en'ds' projecting arms 36 which 38 the rollers35 on the rod 29 escape from the arms 36 and the rod is ciluickl'ythrust downward by the action oft e spring 28. The release ofthe rod 29from the trigger is effected electromagnetically.

9 represents the, armature of the magnet. I

It is supported by a bifurcated carrierpivoted at 10 and 11 to thecasing.

At 9 there is an apertureinto' which is loosely fitted a rod 14. I

14. is a pin in the rod Magainst which the armature can bear, and theaperture 9" is of suchshape that its own swinging movement and thatofthe rod 14 will be compensated for. The rod 14 has a' loop .14", theends of which are pivoted at 14 to the aforesaid arms 36".: If the lowerend of the armature is forced inward it will through the rod 14, and thepin 14 push the trigger device 36 back so as to release the rod 29. Suchaction of the. armature occurs when the current passing through theabove described path becomes too strong for then the magnet 24 and itscore 12 are energized to such an extent asto powerfully draw thearmature inward. i

At 15 there is a push button, which, through rod 15, enables theoperator, when ever he desires, to break the circuit, for by pushinginward upon these parts he thrusts the rod 14 inward, which in turnpushes back. the trigger device at 36 and allows the rod 25) to drop.The push button 15 is not positively connected to the interior releasingmechanism, and merely contacts at its inner end with the outer-end ofthe rod 14 as is shown in Fig. 7. As a result ofthis construction, therod 14: and the parts at tached to it are free to move independently ofthe push button, and it is not therefore posslbleffor the operator tohold the con tacts in closed position by means of the push button if thecurrent should exceed theamountfor which the parts are adjusted. Toenable the operator to restore the contact again, after the circuit hasbeen automatically or otherwise opened, the hand lever at 31 isprovided, the arm 32 of which, slotted at 33, engages with pins or withrollers at 34 on the contact rod 29. By swing ing the lever in theproper direction the rod 29 will be pushed up until the rollers 35 getto points above and rest'upon -the lock arms 86". The under edges ofthese arms are so shaped as to be cam-like and when the roll ers 85strike said under edges they force the trigger-like device backwarduntil they pass the points of the arms. By having the up vper edgescurved in the way described, that is concentric with the axis at 3'2, Iattain important ends. The rollers or pins on the rod 29 cannot act tothrow the trigger in ward, they in fact, when a ward, forcing thetrigger, i anything, out ward toward its active position; but at thesame time, when power is applied to the trigger it rolls with the leastpossible amount of friction under the rollers 35, and consequently thereis a greater assurance that the desired action of circuit breaking shalloccur than is incident to other mechanisms with which I am acquainted.

'lhe armature 9 is normally held separate from the magnet core at 12 bymeans of a spring actuated plunger 13. and the compression spring 13'which controls it zit-rearranged in a casing or cylinder 13 having alongitudinal slot 13 in which a lug 13 on the piston 18 operates, theengagement of this lug with the inner end wall of the slot" tends tolimit the inward movement of the plunger.

13 is a pin carried by the plunger 13. It extends through the cylinderand is adapted to engage with a downwardly projecting lip or ear 9 onthe armature 9. The cylinder 13- has a projecting arm or lug 13 which issecured at 13 to the under-plate of one of the core arms 12 and holdsthe cylinder in position.

It is frequently desirable, especially in locomotives for. electrictraction work, to employ very heavy currents for a few seconds instarting loads and for such purposes I have provided a time limit devicewhich may be employed with the mechanism above described when desired,it being adapted to be adjusted so as to permit a heavy overload to becarried by the circuit for a sufiicicnt time to start the train. it thisoverload continues for too great a period of time the circuit breakerwill operate to break the ressing down- I This plunger circuit, but ifthe overdoad does not eontime for the predetermined limit for which theretarding device is adjusted and the our rent through the circuitdiminishes, the circult breaker will not be opened,

In the drawings, 40 indicates as an entirety a retarding device of astyle preferably for use in connection withthe armature 9 abovedescribed. It comprises an'oil cylinder, ll, communicating at itsrear-end through the duct 41, with an oil receiving chamber 42, and atits front end through a duct ll with an oil receiving chamber 43. 44 1sa duct connecting the said oil receiving chambers a2 and 453.

4 indicates as an entirety a valve which is adapted to control the flowof oil through the duct 44.

46? is a piston or plunger adapted to. opel ate in the cylinder 41 and46 is the plunger rod which is pivotally connected at 46 to a downwardlyprojecting lug 9 arranged at one side of the armature 9.

The cylinder 40 and the oil chambers 42 and 43 may all be formed in asingle cast: mg, as shown in Fig, 8.

47 is a lug or projection on 41 which is secured at 48 to the under sideof one of the legs 15% of the magnet core 12 and serves'to support thecylinder and the parts connected with it in proper position relativetothe armature 9. 1

4A is a conical recess formed at one end of the duct 44.

The control valve comprises a screw threaded stem or rod 49 which ishollow at its inner end as indicated at 49.

50 is a hollow capor valve head which is screwed on to the inner end ofthe valve stem 49, At its inner end 50 it is conically tapered tocorrespond with the recess 44 into which it is adapted tobe adjusted.

50 is a duct leading from the cap 50 and arranged to communicatedirectly with the duct 44. Within the interior of the said cap or valvehead is arranged a spring controlled check valve comprising a ball 51for which a seat is provided at the inner end of the valve stem 49. 52is a spring normally pressing the said ball valve against its seat.

58 is a cap fitted to the outer end wall of the oil reservoir 43 andadapted to receive and guide the valve stem 49.

54 is a stufiing box for the cap 53.

49 is a duct leading from the interior of the hollow end of the valvestem 49 and adapted to establish communication between the oil chamber43 and the interior of the said valve stem.

55 is an index dial or wheel secured to the outer end of the valve stem49. Its periphery is notched as indicatedat 55.

55 is a spring secured at its inner end to the under side of the oilchamber 48 and arranged to have its outer end engage with the thecylinder is i walls of the notches 55 on the dial 55, so

as to hold'the valve stem in any position into which itmay be adjusted.

The oil is introduced into the cylinder 41 and normally fills the spacebetween the plunger and the inner end of the cylinder, the duct 41 andthe oil chamber 42 when the circuit through the mechanism is closed.lVhen an overload on the circuit occurs the magnet 24 tends to draw thelower end of the armature inward as heretofore described. The inwardmovement of the lower end of the armature is opposed by the oil in the.

retarding device. The inward movement of the plunger 46 tends to forcethe oil in the, chamber'42 into thechamber, 43, the

adjustment of the conical end of the head 50 and the walls of the recess44: a.

greater period of time will be required for transmitting-the oil fromthe chamber 42 to the chamber 43 and for the incident travel of'theplunger 46 in order to force the trigger device 36 vback so as torelease "the switch 1.

When the armature 9 of themechanism above described is controlled in itsopera tion by means of a retarding device such as the one hereindescribed, it willbe seen that it is possible to so regulate theretarding device as to predetermine the time during which the overloadmay continue on the circuit. The operation of the retarding device atthe time an over-loadv occurs is as follows: The magnet 12 attracts thearmature 9, which through the rod 46' exerts an. inward pressure on theplunger 46 tending to force the oil as above described from the chamber42 to the chamber 43. If the overload continues for a, long enoughperiod of time, or for a period greater than that for which theretarding action of the check valve is adjusted, the trigger device 36will be forced rearward and the rod 29 will be forced downward under theaction of the spring 28. But if the over-load does not occur for such' apredetermined period of time the circuit through the mechanism will notbe broken. When it is desired to close the circuit after it has beenopened for any reason, the handle 31 is used, and as before describedthe rod 29 is raiscd'until the trigger device 36 locks the said rodagainst downward movement. During this upward movement of the rod 29,the spring 38 acts upon the trigger 3G to force the rod 141- outward.The rod 14: serves by means of the pin 14 to transmit the force of thespring 38 to the'armature 9, and to thus aid in pushingfou'tward thelower end of the armature. As thisend of the armature moves outward itdraws outward the plunger 46 of the retarding device, this tends toforce oil from th chamber {l3 through the duct 49, unseatiii and passingthence intd the chamber 42. Oil may also pass from the chamber 4:3through the conical space between the valve head- 50 and the recess 44to the chamber 42. It will be seen that in viewof the relatively lai gerpassageway, the power necessary to force the oil from the chamber 43 tothe chamber 42 is considerably less than that required for the oppositeaction.

In order to prevent the arcing which occurs between'the stationary andmovable contacts from seriously injuring the closely adjacent metallicparts of the mechanism, I provide to have this arcing take place ininsulated chambers or compartments. These compartments are shown at56-57, Each is a hollow rectangle comprising the bottom insulating plate58 and two side walls or plates of insulating material 59--59 and. thetop plate 60. This rectangle of insulating material is inserted inapertures 61-62 in the side walls- 18"18 of the frame and extends inwardsurrounding both the metal and the carbon contacts within the mechanism. -When the switch 1 is thrown down, breaking the circuit, the arcswhich occur between the brushes are blown out by the magnetic lines offorce passing between the armature 9 and the pole pieces 12"-12 ar--ranged in the rear of the casing. This blowing out of the arcsby thelines of force insures an increased life of the brushes and the factthat this arcing occurs entirely within an insulated compartment insuresthat it will have no detrimental effect upon the metallic parts of themechanism. The walls of the insulatingcompartments, as shown, extendoutward beyond the side walls l8"18 of the casing to keep thefiamesy'from the arcs between the. brushes from contacting with saidwalls.

What I claim is:

1. in a circuit breaker for an electric circuit, the combination of theswitch for opening and closing the circuit, means for throwing theswitch so as to open the circuit, the anti-friction roller carried bysaid switch, and a pivoted trigger device having a curved surfaceconcentric -with the pivot of the device arranged to engage with saidanti-friction roller .to hold the circuit closed andmcansfor releasingsaid trigger device, sub-- stantially as set forth.

2. In a circuit breaker for an electric circuit, the combination withthe stationary brushes and the movable. briishes of means forcontrolling the operation of the movable brushes, comprising a springactuated rod g the valve 51 in valve head 50 i Lorena? havinganti-frictionrollers carried thereby and arran ed on opposite sidesthereof, and a trigger evice adapted to engage with said rollers to holdthe said brushes in contact with each other, substantially as set forth.

8, In a circ s breaker for an electric circuit. the con 'iation with thestationary contacts through which the circuit is closed, of arectilineally movable rod for controlling the movements of the movablecontacts, a spring associated with said rod and adapted to exertpressure thereupon, tending to cause it to open the circuit,anti-friction rollers carried by said rod on opposite sides thereof, atrigger device having arms adapted to engage said rollers to hold thecircuit through the mechanism closed, means for projecting trigger armsinto the path of travel of the said rollers and means for releasingtrigger device, substantially as set forth. I

t, In sire-"it breaker for suits, two contacts, means for h contacts inengagement with cacti electroniagnet having a stationary core, anarmature arranged to form a pole piece for the magnet at one side of thecontacts and arranged to swing away from the said stationary core toopen or completely close an air gap between the core and the armaturethe said armature being adapted to release said holding means for thecontacts, sub stantially as set forth. v

5. in a circuit breaker for an electric circuit, the combination of aswitch, means for automatically opening said. switch, locking devicesattached to said switch, a trigger adapted to engage said lockingdevices and hold the switch in its closed position, said trigger beingadapted to move to permit the movement oflhe switch from its open to itsclosed position, an electro-mag'net, a movable armature for said magnet,a retarding device ccTnnected to said armature and adapted to preventits rapid. movement, and connections between the armature and thetrigger whereby movement of the armature toward the magnet will releasethe trigger, said connections adapted to permit movement of the triggerindependently of the armature, substantially as set iorth,

In a circuit breaker an electric circuit, the combination oi a switch, nnormally holding the switchin swi n a trigger adapted to engage thelocking" device to hold the switch in its closed position, said triggerbeing. adapted to move out of the path of the locking device when theswitch is moved from its open to its closed position, anelectro-mag'net, a movable armature for said electro-ma, let, aretarding device connected to sai' arms ture and adapted to preveinrapid. movement, connecting means between the armature and the triggerwhereby movement of the armature toward the magnet will release thetrigger, said connecting means being adapted to permit movement of thetrigger independently of the armature, and a hand-controlled deviceadapted to engage said connecting means to release the trigger, saidhand-controlled device engaging the connecting means independently ofthe armature, substantially as set forth.

7. In a circuit breaker for an electric circuit, the combination of aswitch, automatic means for moving the switch to its open position, alocking device connected to the switch, a trigger adapted to engage thelocking device to hold the switch in its closed position, said triggerbeing adapted to move out of the path of the locking device when theswitch is moved from its open to its closed position, a releasing deviceconnected to the trigger, a hand-controlled device adaptcd to engage thereleasing device in such a way as tobe capable of moving it only in thedirection to release the trigger, an electro-magnct, a movable armaturefor said magnet, a retarding device connected to the armature andadapted to prevent its rapid movement, said armature engaging saidreleasing device independently of the engagement of the hand-controlleddevice in such a way as to be capable of moving; it only in thedirection to release the trigger, substantially as setforth. a

8. In a circuit breaker for an electriccircuit, the combination of anelectro-mannet having bifurcated core, a stationary switch contact, amovable switch contact, a longitudinally movable rod upon which saidmovable switch contact is supported, said rod extending between the twoprongs of the core, a spring adapted to move the rod to open the switch,a trigger adapted to hold the rod in position with the switch closed, amovable armature mounted adjacent the bifurcated core, and a connectionbetween the armature and the trigger whereby movement of the armaturetoward the core will release the trigger, substantially as set forth.

In a circuit breaker for an electric circuit, the combination of astationary switch contact, a movable switch contact, a longi tudinallymovable rod upon which the movable switch contact is supported, meansfor automaticallymoving the rod to open the switch, a trigger adapted toengage the rod to hold the switch in closed position, an electro-magnethaving a bifurcated core, the two forks of which are located on oppositssides of the said rod, pole pieces on one side of switch contact andmagnetithe cdre will release the trigger and permit In testimony whereofI affix sighs the switch to open, the said poles, core and ture inpresence of tWo witness armature forming a part of a maqnetic cir- Icuit which passes through the sx iiitch coni FRANK SES/LONS' 5 teats andserves to blow out electric arcs be- Witnesses:

tween said contacts, substantially as set (J. E, WAXBORN,

' forth. v R. R. DUNLOP.

